WO2011145189A1 - Fastening structure of ring gear - Google Patents

Abstract

Disclosed is a fastening structure of a ring gear, wherein a ring gear is fastened to a flange of a differential case constituting a differential subassembly. The ring gear has an inner peripheral surface to be press-fitted to the outer peripheral surface of the flange, and is swaged by a swaging portion provided on at least one end of the flange in the axial direction. In order to prevent the ring gear from deforming in the radial direction, an engaging means for engaging the flange with the ring gear using the relationship between a recess and a protrusion is provided. The engaging means is comprised of a recess formed at an end face of the ring gear and a protrusion formed on the flange. The protrusion is engaged in the recess by swaging.

Description

Ring gear fastening structure

The present invention relates to a differential sub-assembly mounted on a vehicle, and more particularly, to a ring gear fastening structure for fastening a ring gear to a differential case constituting the differential sub-assembly.

Conventionally, as a technique of this type, for example, in Patent Document 1 below, in order to fasten a ring gear to a differential case, after the ring gear is press-fitted into the outer peripheral surface of the flange of the differential case, both ends of the ring gear are connected to both ends of the flange. It is described that it is fixed by caulking. A differential subassembly used for a power transmission mechanism of a vehicle can be obtained by assembling predetermined parts in addition to the ring gear to the differential case.

EP0647789B1 publication JP 2001-124181 A

However, when the differential subassembly having the fastening structure described in Patent Document 1 is used in a vehicle power transmission mechanism, the ring gear is elastically deformed by the meshing reaction force when the ring gear meshes with the mating gear. . In this case, a part of the inner peripheral surface (press-fit surface) of the ring gear is separated from the flange of the differential case and becomes a non-uniform surface pressure state, which may reduce the fastening force.

FIG. 14 shows the relationship between the flange 41 of the differential case after tightening and the ring gear 42 in a schematic sectional view by cutting the differential case in the axial direction. 15 and 16, the relationship between the differential case 43 and the ring gear 42 after fastening is shown in a schematic cross-sectional view by cutting the differential case 43 in the radial direction. In FIG. 14, the ring gear 42 is press-fitted onto the outer peripheral surface 45 of the flange 41 at its inner peripheral surface (press-fit surface) 44, and is formed at the other end of the flange 41 and the other end. It is caulked to the flange 41 with the caulking portion 47. In this state, the meshing reaction force F1 generated in the ring gear 42 is transmitted as torque to the differential case 43 by the cooperation of the “caulking portion 47” and “the frictional force against the surface pressure on the press-fit surface 44”. . Here, when the ring gear 42 is not loaded, a uniform surface pressure is generated on the press-fit surface 44 of the ring gear 42 as indicated by an arrow in FIG. On the other hand, when the ring gear 42 is loaded, as shown in FIG. 16, a meshing reaction force F1 is generated in the ring gear 42, whereby the ring gear 42 is elastically deformed, so that a part of the press-fit surface 44 is separated from the differential case 43. As a result, the surface pressure state of the press-fit surface 44 becomes non-uniform. As a result, the total surface pressure on the press-fit surface 44 is reduced, and the torque transmitted from the ring gear 42 to the differential case 43 may be reduced.

Here, a part of the ring gear 42 is shown in a perspective view in FIG. A plurality of notches 48 that are caulked by caulking portions 47 of the flange 41 are formed on the inner peripheral edge of the ring gear 42. Conventionally, caulking portions 47 have been caulked to these notches 48 by plastic working. These notches 48 are formed on the inner side of the ring gear 42, and the caulking is performed so as to expand the flange 41 from the inner side to the outer side. For this reason, in FIG. 14, the caulking portion 47 of the flange 41 does not function in the direction of suppressing the deformation of the ring gear 42 with respect to the direction in which the press-fitting surface 44 of the ring gear 42 moves away from the flange 41.

The present invention has been made in view of the above circumstances, and the object thereof is to maintain a uniform surface pressure state of the inner peripheral surface (press-fit surface) of the ring gear and to obtain a total surface pressure on the inner peripheral surface (press-fit surface). An object of the present invention is to provide a ring gear fastening structure capable of preventing the reduction of the above.

(1) In order to achieve the above object, according to a first aspect of the present invention, there is provided a ring gear fastening structure in which a ring gear is fastened to a flange of a differential case that constitutes a differential sub-assembly. In order to suppress the deformation of the ring gear in the radial direction, it is press-fitted into the outer peripheral surface of the flange at the surface and is caulked by at least one of the both ends in the axial direction of the flange. It is intended that an engaging means for engaging with each other in a concave-convex relationship is provided.

According to the configuration of (1) above, a differential sub-assembly can be obtained by assembling predetermined parts in addition to the ring gear to the differential case. Therefore, when the differential subassembly is used for a power transmission mechanism of a vehicle, a meshing reaction force is generated when the ring gear meshes with the counterpart gear. The ring gear tends to be elastically deformed in the radial direction by the meshing reaction force, but this elastic deformation is suppressed by the engaging means that engages in a concave-convex relationship.

(2) In order to achieve the above object, in the configuration of the above (1), the engaging means includes a concave portion formed on the end face of the ring gear and a convex portion formed on the flange, and the convex portion is caulked. It is preferable to be configured to engage with the recess.

(3) In order to achieve the above object, in the configuration of (1), the engaging means includes a convex portion formed on the end face of the ring gear and a concave portion formed on the flange, and the concave portion is formed on the flange. It is preferable that the formed convex portion is formed by being deformed by caulking.

(4) In order to achieve the above object, in the configuration of (1) above, the engaging means is formed on the flange formed on the end surface of the ring gear and the flange, and when the ring gear is press-fitted onto the outer peripheral surface of the flange. It is preferable to include a concave portion with which the convex portion engages.

According to the configuration of (4), it is not necessary to deform the convex portion as compared with the configuration of (2) or (3).

(5) In order to achieve the above object, in the configuration of (4) above, the convex portion includes an engaging surface that is inclined in the press-fitting direction of the ring gear and engages with the engaged surface of the concave portion. It is preferable that the surface is inclined in the press-fitting direction of the ring gear, and the inclination angle of the engaging surface is larger than the inclination angle of the engaged surface.

According to the configuration of the above (5), in addition to the operation of the configuration of the above (4), the convex portion is press-fitted into the concave portion, whereby the relationship between the inclination angle of the engaging surface and the inclination angle of the engaged surface is obtained. The concave portion is expanded by the convex portion.

According to the configuration of the invention, the surface pressure state of the inner peripheral surface (press-fit surface) of the ring gear can be kept uniform, and the reduction of the total surface pressure on the inner peripheral surface (press-fit surface) can be prevented. .

The side view which concerns on 1st Embodiment and shows schematic structure of a differential sub-assembly. FIG. 4 is a cross-sectional view schematically showing a relationship between a flange of a differential case and a ring gear according to the embodiment. Sectional drawing which concerns on the embodiment and shows roughly the press-fit process of the fastening method. Sectional drawing which concerns on the embodiment and shows roughly the press-fit process of the fastening method. Sectional drawing which concerns on the same embodiment and shows the crimping process of the fastening method roughly. Sectional drawing which concerns on 2nd Embodiment and shows schematically the relationship between the flange of a differential case, and a ring gear. Sectional drawing which concerns on the embodiment and shows roughly the press-fit process of the fastening method. Sectional drawing which concerns on the embodiment and shows roughly the press-fit process of the fastening method. Sectional drawing which concerns on the same embodiment and shows the crimping process of the fastening method roughly. Sectional drawing which concerns on 3rd Embodiment and shows schematically the relationship between the flange of a differential case, and a ring gear. Sectional drawing which isolate | separates and shows a flange and a ring gear concerning the embodiment. Sectional drawing which concerns on the embodiment and shows roughly the press-fit process of the fastening method. Sectional drawing which concerns on the same embodiment and shows the crimping process of the fastening method roughly. Sectional drawing which concerns on a prior art example and shows the relationship between the flange of a differential case, and a ring gear. Sectional drawing which concerns on a prior art example and shows schematically the relationship between the differential case and ring gear at the time of no load. Sectional drawing which concerns on a prior art example and shows schematically the relationship between the differential case at the time of load and a ring gear. The perspective view which concerns on a prior art example and shows a part of ring gear.

<First Embodiment>
DESCRIPTION OF EMBODIMENTS Hereinafter, a first embodiment in which a ring gear fastening structure according to the present invention is embodied will be described in detail with reference to the drawings.

FIG. 1 is a side view showing a schematic configuration of the differential sub-assembly 1. FIG. 2 is a schematic sectional view showing the relationship between the flange 3 of the differential case 2 and the ring gear 4. As shown in FIG. 1, the differential sub-assembly 1 includes a differential case 2, a flange 3 provided on the outer periphery of one end side (the left side of the drawing) of the differential case 2, and a ring gear 4 having an annular shape fastened to the outer periphery of the flange 3. With. A pair of side gears and a pair of pinions (both not shown) are accommodated in the differential case 2 in a state of being rotatably supported.

This differential sub assembly 1 is used for a power transmission mechanism of a vehicle. For example, in a vehicle, it is provided for a transmission, a transfer, a final reduction gear, and the like. The power input to the ring gear 4 from the other gear (not shown) is transmitted to a rotating member connected to the pair of pinions while allowing a rotational difference between the pair of side gears. . Here, examples of the rotating member include a pair of left and right drive wheels and a pair of front and rear drive axles of the vehicle.

As shown in FIGS. 1 and 2, in this embodiment, the ring gear 4 is constituted by a helical gear, and a plurality of teeth 11 provided on the outer periphery are formed obliquely with respect to the axial direction of the ring gear 4. . The ring gear 4 is press-fitted into the outer peripheral surface 21 of the flange 3 by the press-fitting surface 12 that is the inner peripheral surface thereof, and is caulked by the flange 3. That is, the first caulking portion 22 is formed on one end side in the axial direction of the flange 3 (left side in FIG. 2). The ring gear 4 has a plurality of notches 13 obliquely formed as caulking portions that are caulked by the first caulking portions 22 at the inner peripheral edge of one end in the axial direction thereof. These notches 13 are the same as the conventional notches 48 shown in FIG.

Further, in this embodiment, in order to suppress the deformation of the ring gear 4 in the radial direction, an engagement means that engages in an uneven relationship is provided between the flange 3 and the ring gear 4. That is, the second caulking portion 23 as a convex portion of the present invention is formed on the other end side (the right side in FIG. 2) of the flange 3 in the axial direction. The second caulking portion 23 may be formed continuously along the outer periphery of the flange 3 or may be formed intermittently along the outer periphery. In addition, a circumferential groove 15 that engages with the second caulking portion 23 in an uneven relationship is formed on one end surface 14 of the ring gear 4. The circumferential groove 15 may be formed continuously along the circumference of the one end face 14 of the ring gear 4 so as to match the second caulking portion 23, and intermittently along the circumference of the one end face 14. It may be formed. In this embodiment, the engagement means described above is configured by the second caulking portion 23 and the circumferential groove 15.

Then, the notch 13 of the ring gear 4 is caulked by the first caulking portion 22, and the one end face 14 of the ring gear 4 is second caulked so that the tip of the second caulking portion 23 is engaged with the circumferential groove 15 of the ring gear 4. It is caulked by the part 23. In this manner, a ring gear fastening structure in which the ring gear 4 is fastened to the flange 3 of the differential case 2 is configured.

Next, a method for fastening the ring gear in this embodiment will be described. 3 to 5 show the respective steps of the fastening method by a schematic cross-sectional view similar to FIG.

First, in the “press-fitting process”, as shown in FIGS. 3 and 4, the ring gear 4 is press-fitted into the outer peripheral surface 21 of the flange 3 by the press-fitting surface 12. At this time, the first caulking portion 22 of the flange 3 extends in parallel with the outer peripheral surface 21, and the second caulking portion 23 extends at a right angle to the outer peripheral surface 21. Further, as shown in FIG. 4, the ring gear 4 is pushed and press-fitted until its one end face 14 comes into contact with the second caulking portion 23. In this state, the press-fit surface 12 of the ring gear 4 is in close contact with the outer peripheral surface 21 of the flange 3.

Thereafter, in the “caulking step”, the first caulking portion 22 of the flange 3 is pressed against the notch 13 of the ring gear 4 as shown in FIG. Further, the second caulking portion 23 of the flange 3 is pressed against the one end surface 14 of the ring gear 4 and the tip end portion of the second caulking portion 23 is caulked so as to be engaged with the circumferential groove 15 of the ring gear 4. In this state, the ring gear 4 is positioned and fixed with respect to the flange 3 in the axial direction and the radial direction.

According to the fastening structure of the ring gear in this embodiment described above, when the differential subassembly 1 is used for a power transmission mechanism of a vehicle, the ring gear 4 meshes with the counterpart gear, and as shown by an arrow in FIG. A meshing reaction force F <b> 1 is generated, and a pressing force F <b> 2 is generated on the press-fitting surface 12 of the ring gear 4. The ring reaction force F1 causes the ring gear 4 to be elastically deformed in the radial direction, but this elastic deformation is suppressed by the second caulking portion 23 and the circumferential groove 15 that are engaged in an uneven relationship. For this reason, part of the press-fit surface 12 of the ring gear 4 is prevented from separating from the outer peripheral surface 21 of the differential case 3, and the surface pressure state of the press-fit surface 12 can be kept uniform. As a result, a reduction in the total surface pressure on the press-fitting surface 12 can be suppressed, and a decrease in torque transmitted from the ring gear 4 to the differential case 2 can be suppressed.

Second Embodiment
Next, a second embodiment in which the ring gear fastening structure according to the present invention is embodied will be described in detail with reference to the drawings.

In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described.

FIG. 6 shows the relationship between the flange 3 of the differential case 2 and the ring gear 4 by a schematic cross-sectional view similar to FIG. This embodiment differs from the first embodiment in the configuration of the engaging means. That is, in this embodiment, as shown in FIG. 6, the engaging means is formed at one end edge of the flange portion 16 as the convex portion of the present invention formed on one end surface of the ring gear 4 and the flange 3 of the differential case 2. And a circumferential groove 24 as a concave portion of the present invention. In this embodiment, the flange portion 16 extends parallel to the press-fit surface 12 of the ring gear 4 and protrudes from the one end surface 14. The circumferential groove 24 is formed by caulking the second caulking portion 23 formed at one end edge of the flange 3 against the flange portion 16. In this state, the flange portion 16 of the ring gear 4 is engaged with the circumferential groove 24 of the flange 3, and deformation of the ring gear 4 in the radial direction is suppressed. The configuration of the first caulking portion 22 and the notch 13 is the same as that of the first embodiment.

Next, a method for fastening the ring gear in this embodiment will be described. 7 to 9 show the respective steps of the fastening method by a schematic cross-sectional view similar to FIG.

First, in the “press-fitting process”, the ring gear 4 is press-fitted into the outer peripheral surface 21 of the flange 3 with the press-fitting surface 12 as shown in FIGS. At this time, the first caulking portion 22 of the flange 3 extends in parallel with the outer peripheral surface 21, and the second caulking portion 23 extends at a right angle to the outer peripheral surface 21. Further, as shown in FIG. 8, the ring gear 4 is pushed and press-fitted until the front end of the flange portion 16 comes into contact with the second caulking portion 23. In this state, the press-fit surface 12 of the ring gear 4 is in close contact with the outer peripheral surface 21 of the flange 3.

Thereafter, in the “caulking step”, the first caulking portion 22 of the flange 3 is pressed against the notch 13 of the ring gear 4 as shown in FIG. Further, the second caulking portion 23 of the flange 3 is caulked so as to be pressed against the flange portion 16 of the ring gear 4. Accordingly, the flange portion 16 of the ring gear 4 is engaged with the circumferential groove 24 of the flange 3. In this state, the ring gear 4 is positioned and fixed with respect to the flange 3 in the axial direction and the radial direction.

Therefore, even in this embodiment, even if the ring gear 4 tries to elastically deform in the radial direction due to the meshing reaction force, the elastic deformation is suppressed by the engagement between the flange portion 16 of the ring gear 4 and the circumferential groove 24 of the flange 3. For this reason, part of the press-fit surface 12 of the ring gear 4 is prevented from separating from the outer peripheral surface 21 of the differential case 3, and the surface pressure state of the press-fit surface 12 can be kept uniform. As a result, a reduction in the total surface pressure on the press-fitting surface 12 can be suppressed, and a decrease in torque transmitted from the ring gear 4 to the differential case 2 can be suppressed.

<Third Embodiment>
Next, a third embodiment in which the ring gear fastening structure of the present invention is embodied will be described in detail with reference to the drawings.

FIG. 10 shows a relationship between the flange 3 of the differential case 2 and the ring gear 4 by a schematic cross-sectional view similar to FIG. This embodiment is also different from the first and second embodiments in the configuration of the engaging means. That is, in this embodiment, as shown in FIG. 10, the engaging means is provided at one end edge of the flange portion 16 as the convex portion of the present invention formed on one end surface 14 of the ring gear 4 and the flange 3 of the differential case 2. And a circumferential groove 25 as a recess of the present invention formed. In this embodiment, the flange portion 16 is the same as that of the second embodiment. Further, the circumferential groove 25 is formed in advance inside the bank portion 26 formed at one end edge of the flange 3.

FIG. 11 is a schematic sectional view showing the flange 3 and the ring gear 4 separated. In this embodiment, the flange portion 16 of the ring gear 4 is inclined in the press-fitting direction with respect to the flange 3 of the ring gear 4, and includes an engagement surface 16 a that engages with the engaged surface 25 a of the circumferential groove 25 of the flange 3. The engagement surface 16 a has a predetermined inclination angle α that is inclined with respect to the press-fit surface 12. The engaged surface 25 a of the circumferential groove 25 is inclined in the press-fitting direction of the ring gear 4 and has a predetermined inclination angle β that is inclined with respect to the outer peripheral surface 21 of the flange 3. In this embodiment, the inclination angle α of the engaging surface 16a is set to be larger than the inclination angle β of the engaged surface 25a.

Then, as shown in FIG. 10, the flange portion 16 of the ring gear 4 is engaged with the circumferential groove 25 of the flange 3, whereby the radial deformation of the ring gear 4 is suppressed. The configuration of the first caulking portion 22 and the notch 13 is the same as that of the first embodiment.

Next, a method for fastening the ring gear in this embodiment will be described. 12 and 13 are schematic sectional views according to FIG. 2 showing each step of the fastening method.

First, in the “press-fit process”, as shown in FIG. 12, the ring gear 4 is press-fitted into the outer peripheral surface 21 of the flange 3 by the press-fit surface 12. At this time, the first caulking portion 22 of the flange 3 extends in parallel with the outer peripheral surface 21. The ring gear 4 is pushed and press-fitted until the flange portion 16 engages with the circumferential groove 25 of the flange 3. In this state, the press-fit surface 12 of the ring gear 4 is in close contact with the outer peripheral surface 21 of the flange 3. Further, when the flange portion 16 is press-fitted into the circumferential groove 25, the circumferential groove 25 is expanded by the flange portion 16 due to the relationship between the inclination angle α of the engaging surface 16a and the inclination angle β of the engaged surface 25a. It becomes a state. Therefore, as shown in FIG. 12, a surface pressure is generated between the engaging surface 16a and the engaged surface 25a as shown by arrows A1 and A2.

Thereafter, in the “caulking process”, the first caulking portion 22 of the flange 3 is pressed against the notch 13 of the ring gear 4 as shown in FIG. In this state, the ring gear 4 is positioned and fixed with respect to the flange 3 in the axial direction and the radial direction.

Therefore, even in this embodiment, even if the ring gear 4 tries to elastically deform in the radial direction due to the meshing reaction force, this elastic deformation is suppressed by the engagement between the flange portion 16 of the ring gear 4 and the circumferential groove 25 of the flange 3. For this reason, part of the press-fit surface 12 of the ring gear 4 is prevented from separating from the outer peripheral surface 21 of the differential case 3, and the surface pressure state of the press-fit surface 12 can be kept uniform. As a result, a reduction in the total surface pressure on the press-fitting surface 12 can be suppressed, and a decrease in torque transmitted from the ring gear 4 to the differential case 2 can be suppressed.

In this embodiment, as shown in FIGS. 12 and 13, surface pressure is generated between the engaging surface 16 a of the flange portion 16 and the engaged surface 25 a of the circumferential groove 25, so in the second embodiment, The same effect as when the flange portion 16 is caulked with the second caulking portion 23 is obtained. For this reason, it is possible to simplify the “caulking process” while obtaining the same caulking effect as in the second embodiment.

In addition, this invention is not limited to each said embodiment, A part of structure can also be changed suitably and implemented in the range which does not deviate from the meaning of invention.

The present invention can be used for a differential sub-assembly used in a vehicle power transmission mechanism.

1 Differential sub-assy 2 Differential case 3 Flange 4 Ring gear 12 Press-fit surface (inner peripheral surface)
13 Notch 14 One end face 15 Circumferential groove (recess)
16 Flange (convex)
16a engagement surface 21 outer peripheral surface 22 first caulking portion 23 second caulking portion (convex portion)
24 Circumferential groove (recess)
25 Circumferential groove (recess)
25a engaged surface

Claims (5)

A ring gear fastening structure in which a ring gear is fastened to a flange of a differential case constituting a differential sub-assembly,
The ring gear is press-fitted into the outer peripheral surface of the flange at an inner peripheral surface thereof, and is caulked by caulking portions provided at at least one of both ends in the axial direction of the flange. In order to suppress deformation, a ring gear fastening structure is provided, wherein an engaging means is provided between the flange and the ring gear so as to engage in a concave-convex relationship. The engagement means includes a recess formed on an end face of the ring gear and a projection formed on the flange, and the projection engages the recess by caulking. The fastening structure of the ring gear as described in 2. The engaging means includes a convex portion formed on an end surface of the ring gear and a concave portion formed on the flange, and the concave portion is formed by deforming the convex portion formed on the flange by caulking. The ring gear fastening structure according to claim 1, wherein: The engaging means includes a convex portion formed on an end surface of the ring gear, and a concave portion formed on the flange and engaged with the convex portion when the ring gear is press-fitted into the outer peripheral surface of the flange. The ring gear fastening structure according to claim 1, wherein the ring gear is fastened. The convex portion includes an engagement surface that is inclined in the press-fitting direction of the ring gear and is engaged with an engaged surface of the concave portion, and the engaged surface is inclined in the press-fitting direction of the ring gear, and the engagement The ring gear fastening structure according to claim 4, wherein an inclination angle of a surface is larger than an inclination angle of the engaged surface.

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